Is it possible to change operator's bl_label on the fly?
Manipulating an operator type once registered isn't supported. *

Your options are:


override the label when drawing the interface. eg:layout.operator("some.op", text=label_override)
Modify the class, then re-register the operator(unregister() &amp; register())


Hint, if you want to do a conditional override, Python can do this by passing a dictionary...

keyword_args = {}
if some_test:
    keyword_args["text"] = label_override
layout.operator("some.op", **keyword_args)




* (unless you modify the memory directly, which is possible but outside the scope of Blender/Python API).